ref: d376fac66cbd5efbe2f9f61a1e8b31af03a84a92
dir: /sys/src/9/port/devsegment.c/
#include "u.h" #include "../port/lib.h" #include "mem.h" #include "dat.h" #include "fns.h" #include "../port/error.h" enum { Qtopdir, Qsegdir, Qctl, Qdata, }; #define TYPE(x) (int)( (c)->qid.path & 0x7 ) #define SEG(x) ( ((c)->qid.path >> 3) & 0x3f ) #define PATH(s, t) ( ((s)<<3) | (t) ) typedef struct Globalseg Globalseg; struct Globalseg { Ref; char *name; char *uid; vlong length; long perm; Segio; }; static Globalseg *globalseg[100]; static Lock globalseglock; Segment* (*_globalsegattach)(char*); static Segment* globalsegattach(char *name); static Segment* fixedseg(uintptr va, ulong len); /* * returns with globalseg incref'd */ static Globalseg* getgseg(Chan *c) { int x; Globalseg *g; x = SEG(c); lock(&globalseglock); if(x >= nelem(globalseg)) panic("getgseg"); g = globalseg[x]; if(g != nil) incref(g); unlock(&globalseglock); if(g == nil) error("global segment disappeared"); return g; } static void putgseg(Globalseg *g) { if(g == nil || decref(g)) return; if(g->s != nil) putseg(g->s); segio(g, nil, nil, 0, 0, 0); free(g->name); free(g->uid); free(g); } static int segmentgen(Chan *c, char*, Dirtab*, int, int s, Dir *dp) { Qid q; Globalseg *g; uintptr size; switch(TYPE(c)) { case Qtopdir: if(s == DEVDOTDOT){ q.vers = 0; q.path = PATH(0, Qtopdir); q.type = QTDIR; devdir(c, q, "#g", 0, eve, 0777, dp); break; } if(s >= nelem(globalseg)) return -1; lock(&globalseglock); g = globalseg[s]; if(g == nil){ unlock(&globalseglock); return 0; } q.vers = 0; q.path = PATH(s, Qsegdir); q.type = QTDIR; kstrcpy(up->genbuf, g->name, sizeof up->genbuf); devdir(c, q, up->genbuf, 0, g->uid, 0777, dp); unlock(&globalseglock); break; case Qsegdir: if(s == DEVDOTDOT){ q.vers = 0; q.path = PATH(0, Qtopdir); q.type = QTDIR; devdir(c, q, "#g", 0, eve, 0777, dp); break; } /* fall through */ case Qctl: case Qdata: switch(s){ case 0: g = getgseg(c); q.vers = 0; q.path = PATH(SEG(c), Qctl); q.type = QTFILE; devdir(c, q, "ctl", 0, g->uid, g->perm, dp); putgseg(g); break; case 1: g = getgseg(c); q.vers = 0; q.path = PATH(SEG(c), Qdata); q.type = QTFILE; if(g->s != nil) size = g->s->top - g->s->base; else size = 0; devdir(c, q, "data", size, g->uid, g->perm, dp); putgseg(g); break; default: return -1; } break; } return 1; } static void segmentinit(void) { _globalsegattach = globalsegattach; } static Chan* segmentattach(char *spec) { return devattach('g', spec); } static Walkqid* segmentwalk(Chan *c, Chan *nc, char **name, int nname) { return devwalk(c, nc, name, nname, 0, 0, segmentgen); } static int segmentstat(Chan *c, uchar *db, int n) { return devstat(c, db, n, 0, 0, segmentgen); } static Chan* segmentopen(Chan *c, int omode) { Globalseg *g; switch(TYPE(c)){ case Qsegdir: omode &= ~ORCLOSE; case Qtopdir: if(omode != 0) error(Eisdir); break; case Qctl: case Qdata: g = getgseg(c); if(waserror()){ putgseg(g); nexterror(); } devpermcheck(g->uid, g->perm, omode); if(TYPE(c) == Qdata && g->s == nil) error("segment not yet allocated"); c->aux = g; poperror(); break; default: panic("segmentopen"); } c->mode = openmode(omode); c->flag |= COPEN; c->offset = 0; return c; } static void segmentremove(Chan *c) { Globalseg *g; int x; if(TYPE(c) != Qsegdir) error(Eperm); lock(&globalseglock); x = SEG(c); g = globalseg[x]; globalseg[x] = nil; unlock(&globalseglock); if(g != nil) putgseg(g); } static void segmentclose(Chan *c) { if(c->flag & COPEN){ switch(TYPE(c)){ case Qsegdir: if(c->flag & CRCLOSE) segmentremove(c); break; case Qctl: case Qdata: putgseg(c->aux); c->aux = nil; break; } } } static Chan* segmentcreate(Chan *c, char *name, int omode, ulong perm) { int x, xfree; Globalseg *g; if(TYPE(c) != Qtopdir) error(Eperm); if(strlen(name) >= sizeof(up->genbuf)) error(Etoolong); if(findphysseg(name) != nil) error("name collision with physical segment"); if((perm & DMDIR) == 0) error(Ebadarg); g = smalloc(sizeof(Globalseg)); g->ref = 1; g->perm = 0660; kstrdup(&g->name, name); kstrdup(&g->uid, up->user); lock(&globalseglock); if(waserror()){ unlock(&globalseglock); putgseg(g); nexterror(); } xfree = -1; for(x = 0; x < nelem(globalseg); x++){ if(globalseg[x] == nil){ if(xfree < 0) xfree = x; } else if(strcmp(globalseg[x]->name, name) == 0) error(Eexist); } if(xfree < 0) error("too many global segments"); globalseg[xfree] = g; unlock(&globalseglock); poperror(); c->qid.path = PATH(xfree, Qsegdir); c->qid.type = QTDIR; c->qid.vers = 0; c->mode = openmode(omode); c->flag |= COPEN; c->offset = 0; return c; } static long segmentread(Chan *c, void *a, long n, vlong voff) { Globalseg *g; char buf[128]; if(c->qid.type == QTDIR) return devdirread(c, a, n, (Dirtab *)0, 0L, segmentgen); g = c->aux; switch(TYPE(c)){ case Qctl: if(g->s == nil) error("segment not yet allocated"); if((g->s->type&SG_TYPE) == SG_FIXED) snprint(buf, sizeof(buf), "va %#p %#p fixed %#p\n", g->s->base, g->s->top-g->s->base, g->s->map[0]->pages[0]->pa); else if((g->s->type&SG_TYPE) == SG_STICKY) snprint(buf, sizeof(buf), "va %#p %#p sticky\n", g->s->base, g->s->top-g->s->base); else snprint(buf, sizeof(buf), "va %#p %#p\n", g->s->base, g->s->top-g->s->base); return readstr(voff, a, n, buf); case Qdata: return segio(g, g->s, a, n, voff, 1); default: panic("segmentread"); } return 0; /* not reached */ } static long segmentwrite(Chan *c, void *a, long n, vlong voff) { Cmdbuf *cb; Globalseg *g; uintptr va, top, len; if(c->qid.type == QTDIR) error(Eperm); g = c->aux; switch(TYPE(c)){ case Qctl: cb = parsecmd(a, n); if(waserror()){ free(cb); nexterror(); } if(cb->nf > 0 && strcmp(cb->f[0], "va") == 0){ if(g->s != nil) error("already has a virtual address"); if(cb->nf < 3) error(Ebadarg); va = strtoull(cb->f[1], 0, 0); len = strtoull(cb->f[2], 0, 0); top = PGROUND(va + len); va = va&~(BY2PG-1); if(va == 0 || top > USTKTOP || top <= va) error(Ebadarg); len = top - va; if(len > SEGMAXSIZE) error(Enovmem); if(cb->nf >= 4 && strcmp(cb->f[3], "fixed") == 0){ if(!iseve()) error(Eperm); g->s = fixedseg(va, len/BY2PG); } else if(cb->nf >= 4 && strcmp(cb->f[3], "sticky") == 0){ Segment *s; if(!iseve()) error(Eperm); s = newseg(SG_STICKY, va, len/BY2PG); if(waserror()){ putseg(s); nexterror(); } for(; va < s->top; va += BY2PG) segpage(s, newpage(1, nil, va)); poperror(); g->s = s; } else g->s = newseg(SG_SHARED, va, len/BY2PG); } else error(Ebadctl); free(cb); poperror(); return n; case Qdata: return segio(g, g->s, a, n, voff, 0); default: panic("segmentwrite"); } return 0; /* not reached */ } static int segmentwstat(Chan *c, uchar *dp, int n) { Globalseg *g; Dir *d; if(c->qid.type == QTDIR) error(Eperm); g = getgseg(c); if(waserror()){ putgseg(g); nexterror(); } if(strcmp(g->uid, up->user) && !iseve()) error(Eperm); d = smalloc(sizeof(Dir)+n); if(waserror()){ free(d); nexterror(); } n = convM2D(dp, n, &d[0], (char*)&d[1]); if(n == 0) error(Eshortstat); if(!emptystr(d->uid)) kstrdup(&g->uid, d->uid); if(d->mode != ~0UL) g->perm = d->mode&0777; free(d); poperror(); putgseg(g); poperror(); return n; } /* * called by segattach() */ static Segment* globalsegattach(char *name) { int x; Globalseg *g; Segment *s; lock(&globalseglock); if(waserror()){ unlock(&globalseglock); nexterror(); } for(x = 0; x < nelem(globalseg); x++){ g = globalseg[x]; if(g != nil && strcmp(g->name, name) == 0) goto Found; } unlock(&globalseglock); poperror(); return nil; Found: devpermcheck(g->uid, g->perm, ORDWR); s = g->s; if(s == nil) error("global segment not assigned a virtual address"); incref(s); unlock(&globalseglock); poperror(); return s; } /* * allocate a fixed segment with sequential run of of adjacent * user memory pages. */ static Segment* fixedseg(uintptr va, ulong len) { KMap *k; Segment *s; Page **f, *p, *l, *h, *t; ulong n, i; int color; s = newseg(SG_FIXED, va, len); if(waserror()){ putseg(s); nexterror(); } lock(&palloc); i = 0; l = palloc.pages; color = getpgcolor(va); for(n = palloc.user; n >= len; n--, l++){ if(l->ref != 0 || i != 0 && (l[-1].pa+BY2PG) != l->pa || i == 0 && l->color != color){ Retry: i = 0; continue; } if(++i < len) continue; i = 0; h = t = nil; f = &palloc.head; while((p = *f) != nil){ if(p > &l[-len] && p <= l){ *f = p->next; if((p->next = h) == nil) t = p; h = p; if(++i < len) continue; break; } f = &p->next; } if(i != len){ if(h != nil){ t->next = palloc.head; palloc.head = h; } goto Retry; } palloc.freecount -= i; unlock(&palloc); p = &l[-len]; do { p++; p->ref = 1; p->va = va; p->modref = 0; settxtflush(p, 1); k = kmap(p); memset((void*)VA(k), 0, BY2PG); kunmap(k); segpage(s, p); va += BY2PG; } while(p != l); poperror(); return s; } unlock(&palloc); error(Enomem); return nil; } Dev segmentdevtab = { 'g', "segment", devreset, segmentinit, devshutdown, segmentattach, segmentwalk, segmentstat, segmentopen, segmentcreate, segmentclose, segmentread, devbread, segmentwrite, devbwrite, segmentremove, segmentwstat, };